1. Field of the Invention
This invention relates to a scroll type compressor, and more particularly, to an oil separating mechanism for separating lubricating oil from refrigerant gas in a hermetically sealed scroll type compressor.
2. Description of the Prior Art
A hermetically sealed scroll type compressor is disclosed in Japanese Patent Application Publication No. 61-87994 and is shown in FIG. 1. A hermetically sealed housing includes inner chamber 1 which is maintained at discharge pressure The compression mechanism, including inner fitting scrolls 2 and 3 and the forward end of the drive mechanism including drive shaft 130, are disposed between partition 110 and the end plate of stationery scroll 2, and are isolated from inner chamber 1. A plurality of fluid pockets are formed between the spiral portions of inner fitting scrolls 2 and 3. Channel 5 extends through the end plate of orbiting scroll 3 and links intermediate fluid pocket 6 with isolated chamber 7 formed between the end plate of orbiting scroll 3 and partition 110.
In operation, refrigerant gas flows through inlet port 850 and is compressed inwardly by scrolls 2 and 3 towards central fluid pocket 700 due to orbiting motion of orbiting scroll 3. Compressed fluid in central pocket 700 is discharged into discharge chamber 500 through hole 240 extending through the end plate of stationery scroll 2, and thereafter flows to one of the external elements of the refrigerating system through outlet port 860. Additionally, some of the refrigerant gas discharged from hole 240 also flows into inner chamber 1 and is collected therein. After circulating through the refrigeration system, the refrigerant gas which exits through outlet port 860 returns to the compressor.
The discharged refrigerant gas includes lubricating oil mixed therewith as a mist. The lubricating oil mixed with the discharged refrigerant gas will flow to the external elements of the refrigeration system with the discharged refrigerant gas, decreasing the refrigerating efficiency of the refrigeration system. In order to prevent a decrease in the refrigerating efficiency of the system, the lubricating oil must be separated from the discharged refrigerant gas before it flows from outlet port 860.
As disclosed in Japanese Utility Model Application Publication No. 57-69991 and Japanese Patent Application Publication No. 61-205386, an oil separating member may be disposed within the compressor casing to separate the lubricating oil from the refrigerant gas before it is discharged from the compressor. In the '991 application, the outlet port is moved to a location on the right side surface of the compressor so that its longitudinal axis is parallel to the axis of the drive shaft. An oil separating member is disposed within the compressor housing, in an area forward of the outlet port and extending across the inner chamber of the compressor housing. In the '386 application, the oil separating member is disposed on the rear surface of the end plate of the stationery scroll, at a location where it would cover hole 240 in FIG. 1.
In both prior art applications, the lubricating oil intermixed with the compressed refrigerant gas is retained on the surface of the oil separating member as the refrigerant gas moves therethrough, thereby separating the oil from the compressed refrigerant gas. The separated oil forms drops on the oil separating member, and when the drops reach a certain size, they fall from the oil separating member and are collected at the bottom of the compressor housing. In the '386 application, the oil collected at the bottom of the compressor housing flows in to the isolated chamber to lubricate frictional engaging surfaces of the compressor, due to the pressure difference between the discharge chamber and the isolated chamber which is maintained at an intermediate pressure.
However, provision of an oil separating member within the compressor housing complicates the inner structure of the compressor housing, and thereby increases the complications encountered in the process of assembling the compressor. As a result, the manufacturing cost of the compressor is increased.